Recently, demands for low-end compact printing apparatuses are increasing, and further cost reduction is required.
In order to prevent erroneous conveyance of a print sheet loaded in the feed cassette instead of a print sheet which should be originally fed from the manual feed port, there is proposed an example of the configuration of a printing apparatus and host computer in which an offline job command is embedded in data transmitted from the host computer, and the printer CPU interprets the command to stop the operation of the printing apparatus on the basis of the interpretation so as to prevent an execution timing error between printing and feed of a print sheet to the manual feed port (e.g., Japanese Patent Laid-Open No. 11-316660).
Japanese Patent Laid-Open No. 01-069431 discloses an example in which the feed cassette and manual feed port are mechanically switched to prevent erroneous conveyance of a print sheet.
However, in adjusting the timing from the feed port, the techniques in Japanese Patent Laid-Open Nos. 11-316660 and 01-069431 inhibit implementation of the above-mentioned low-end compact printing apparatus.
For example, in implementing the low-end compact printing apparatus, low cost can be achieved by arranging, as a mechanism compatible with cost reduction, a portion common to the convey path of a print sheet supplied from the feed cassette and that of a print sheet supplied from the manual feed port.
In Japanese Patent Laid-Open No. 01-069431, an expensive CPU is essential to interpret an offline command by the printer CPU. In order to implement a dedicated sensor and a configuration for mechanically switching between the feed cassette and the manual feed port, the number of components inevitably increases, and a dedicated signal processing circuit, a driving source and control circuit for driving the mechanism, and accessory software are indispensable. If the printing apparatus employs this configuration, cost reduction is limited.